WO 00/22948 discloses a process for waterproofing leather and semi manufactured products made up of pieces of leather sewn to each other. This known process comprises a pressing onto the inner surface of the leather of at least one semipermeable membrane, whose surface contacting the leather is provided with a glue pattern. With this arrangement a suitable transpiration of the leather is achieved also in the zones where it is glued to the membrane.
WO 02/11571 discloses instead a process and a device for waterproofing semi manufactured products made of leather or fabric, also joined with other materials, which cannot be completely spread on a table since they have already taken during the manufacture a three-dimensional conformation with at least one inner surface and one outer surface. A typical example of said manufactured products are the uppers of footwear, considered in their final working step, before the application of an inner lining, if any other semi manufactured products of this kind can be boot cuppers, gloves, hats and clothes in general in the final step of their manufacture. Said process comprises the inside out turning of the semi manufactured product and the introduction of a suitably shaped member before the pressing, so as to waterproof the semi manufactured product even if it has already taken a three-dimensional conformation. Said device includes instead a press provided with deformable plates made up of a hollow body having an elastic pressing surface urged outwards by hot air under pressure.
However, said known processes and device, so as they are disclosed in said patent applications, are not particularly suitable per se for an industrial application on a large scale, where a high automation degree is necessary for trying to reduce the manufacture times and costs.
It is therefore an object of the present invention to provide a process and a machine free from said disadvantages, i.e. which can be easily applied to an industrial production. Said object is achieved with a process and a machine described herein.
Thanks to the use of the particular waterproofing sheath shaped and provided with glue, the process and the machine according to the present invention can waterproof the semi manufactured products in a simple and quick manner, so as to allow their automated production, especially if the glue is thermoactivable.
The machine according to the present invention is particularly suitable for the automated production thanks to the deformable plates which are pivoted to a support structure and can press a mobile shaped support suitable for supporting the semi manufactured product and the waterproofing sheath during the pressing.
According to a particular aspect of the invention, the deformable plates can rotate around a substantially vertical axis and the shaped member can run on horizontal rails, so that the operator can easily arrange the semi manufactured product and the waterproofing sheath on the same support.
According to another particular aspect of the invention, the machine is provided with two shaped supports which can be pressed alternately, so that while the first one is pressed, the second one is prearranged by the operator with the semi manufactured product and the waterproofing sheath, and vice versa, so as to double the productivity.
According to a further particular aspect of the invention, the devices for the movement of the mobile components of the machine are driven in a pneumatic manner, so as to simplify its maintenance and to improve its reliability. Further, the particular arrangement of the machine parts prevents the accidental access to the pressing device, so as to improve the overall security.
Another advantage of the process and the machine according to the present invention lies not only in their high productivity, but also in the relatively low costs for their carrying out, so that they can be employed not only in the industrial production, but also in the handicraft production, in particular of footwear.